On Mon, Jul 25, 2011 at 9:41 PM, Manish Katiyar <mkatiyar@xxxxxxxxx> wrote:
> On Mon, Jul 25, 2011 at 9:29 PM, Abhijit Pawar <apawar.linux@xxxxxxxxx> wrote:
>> Hi Dave,
>> On 07/25/2011 09:20 PM, Dave Hylands wrote:
>>> Hi Abhijit,
>>>
>>> On Mon, Jul 25, 2011 at 6:35 AM, Abhijit Pawar<apawar.linux@xxxxxxxxx> wrote:
>>>> On 07/25/2011 05:29 PM, Naveen Kumar wrote:
>>>>
>>>> You can use command ulimit -a, there you can check the limit for a process.
>>>>
>>>> Thanks,
>>>> Naveen
>>>>
>>>> Ulimit gives 1024 as open file limit. In struct task_struct it has a member
>>>> called struct files_struct *files;
>>>>
>>>> I tried checking for this member and the limit however I am not able to
>>>> decide correctly why the limit is 1024.
>>>> Also, is there any distinction between 32 bit and 64 bit systems for this
>>>> limit?
>>> My 64-bit system reports 1024 as well.
>>>
>>> I have no troubles compiling kernels.
>>>
>> Thanks. Yes, on my 64 bit Fedora 15 I get same value as yours.
>>
>> What I am interested in is knowing why the limit is on 1024 File
>> Descriptors? That means 1024 Inodes. AFAIK there isnt anything written
>> in filesystem code which will put this limit of 1024 inodes for a process.
>> This means its very specific to the process.
>> Unfortunately I am know having details on the process front. Is there
>> anything which you or anyone aware in process area because of which this
>> limit is there?
>
> man getdtablesize
and if you trace the kernel code, it comes from the limits of the init
task, which is hard coded during creation. You can get/set these
values using getrlimit/setrlimit.
include/linux/init_task.h
33 #define INIT_SIGNALS(sig) { \
.................
.................
41 .rlim = INIT_RLIMITS,
..............
include/asm-generic/resource.h
72 #define INIT_RLIMITS \
73 { \
74 [RLIMIT_CPU] = { RLIM_INFINITY, RLIM_INFINITY }, \
75 [RLIMIT_FSIZE] = { RLIM_INFINITY, RLIM_INFINITY }, \
76 [RLIMIT_DATA] = { RLIM_INFINITY, RLIM_INFINITY }, \
77 [RLIMIT_STACK] = { _STK_LIM, _STK_LIM_MAX }, \
78 [RLIMIT_CORE] = { 0, RLIM_INFINITY }, \
79 [RLIMIT_RSS] = { RLIM_INFINITY, RLIM_INFINITY }, \
80 [RLIMIT_NPROC] = { 0, 0 }, \
81 [RLIMIT_NOFILE] = { INR_OPEN_CUR, INR_OPEN_MAX }, \
...............
..............
include/linux/fs.h
25 #undef NR_OPEN
26 #define INR_OPEN_CUR 1024 /* Initial setting for nfile rlimits */
27 #define INR_OPEN_MAX 4096 /* Hard limit for nfile rlimits */
HTH
--
Thanks -
Manish
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